Hopes that the professional cycling world might have regained a little serenity after the spate of positive drugs tests during the Tour de France look to have been dashed after events over the weekend, with Luxembourg's Frank Schleck fighting off drugs allegations, and speculation there may be more revelations of cyclists using the latest blood-boosting drug, CERA.

Further tests for CERA - the third-generation anti-anemia drug Continuous Erythropoietin Receptor Activator - will be carried out this week on blood samples from the Tour de France after suspicions were raised among anti-doping testers in the weeks leading up to the world championships. The number of cyclists involved is believed to be between 10 and 14.

During the Tour de France the Italian climber Riccardo Ricco tested positive for the drug, as did another Italian mountain specialist, Emanuele Sella, after tests were carried out on samples from the Giro d'Italia. The previous tests have all been on urine whereas the next phase of analysis will use newly approved blood tests.

As for Schleck, Italian anti-drugs police raided the hotel where he and his team were staying on Friday ahead of the world championships, after a prosecutor in Luxembourg confirmed he had documents showing the cyclist had allegedly made a deposit of close to €7,000 (£5,544) to a Swiss bank account belonging to Eufemiano Fuentes, the gynaecologist at the centre of theMadrid-based blood doping ring unmasked in 2006.

Schleck, who wore the yellow jersey for two days during this year's Tour de France, has maintained his innocence and was permitted to start yesterday's world championship road race in the absence of any proof of wrongdoing. At the Tour, eyebrows were raised when customs officers searched a car driven by his father, Johnny, although nothing incriminating was found. More facts may emerge this week when Schleck meets the prosecutor.

On Saturday, the International Cycling Union president, Pat McQuaid, said the precise date of Lance Armstrong's comeback would depend on when he had registered with a sanctioned drug-testing programme under its "biological passport" rule, which requires athletes to have done so six months before re-entering competition. Armstrong had planned to make his first race the Tour Down Under in Australia in January, but McQuaid said the UCI was investigating whether the American rider, who only confirmed his return to racing this month, had registered in time.